Telephone-exchange system.



E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FIL/ED JUNE 18. 1912. y Patented Sept. 0, 1916.

9 SHEETSSHEET l.

E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNEIB. 1912.

Patented Sept. 5, 1916.

9 SHEETS-SHEET 2.

.ZZ if W E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLlCATlON FILED JUNE 18. 1912.

PatentedSept. 5,1916.

9 SHEETS-SHEET 3.

9 S'HEETSSHEET 4.

Patented Sept. 5

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nrwmmmm E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 18. 1912.

E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED JUNE 18. m2.

Patented Sept 5,1916

9 SHEETSSHEET 5 5 ii I m win W-Ltmmwo E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLlCATlON FILED mm; 18. 1912. l 1W aT b PatentedSept. 5,1916. 9 a 9 SHEETSSHEET e E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM APPLICATION FILED JUNE 18, i912.

Patented Sept. 5, 1916.

9 SHEETSSHEET 7.

LIQWI QQ W q/vitmcowo E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATLQN FILED JUNIE 18, 1912.

Patented Sept. 5, 1916.

9 SHEETSSHEET 8.

avwwwoz E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION EILED JUNE 3.19m

Pmmnted Sept. 5, 1916.

9 SHEETS-SHEET 94 animator EDWARD 1E. CLEMENT, 015 WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO JAMES R. GARFIELD, TRUSTEE, OF CLEVELAND, OHIO.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Sept. 5, 1916.

Application filed June 18, 1912. Serial No. 704,327.

To all whom it may concern.

Be it known that I, EDWARD E. CLEMENT, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Telephone-Exchange -Systems, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to telephone exchange systems, and has for its object to provide automatic switching means which will be automatically self-actuating, and will control preselecting means as for example subscribers or central office senders, within limits determined by such means; or in other words, this system contemplates that the switches shall send back impulses the length of which will be determined by their own time constants, to step or otherwise actuate the sending devices, which by operating to cut off at a fixed or zero position, will determine the number of impulses and thereby the extent of actuationof the switches.

The present application is in the nature of an improvement over my prior applicationsas follows: Serial No. 611,923, filed: March 2, 1911, and Serial No. 644,076, filed August 15, 1911. I

The invention is illustrated in the accompanying drawings in which- Figure 1 is a diagram of a simple embodiment of the invention, and is to be read in conjunction with Fig. 1 Fig. 1 is a similar diagram of a modified form of the invention, and is to be read in conjunction with Figs. 1 and 1. Fig. .1" is :1 dia gram of a subscribers line circuit and central office primary and secondary connecting means. Fig. 1 is a diagram showing selector and connector switches. 'Figs. 2, 3. 4, 5 and 6 taken together containa complete diagram of a commercial semi-automatic system embodying the same principle as Fig. 1. In this form a key set is employed for controlling the impulses.

Referring to Fig. 1, the substation 653 is shown equipped with a standard common battery telephone set, from which the line wires 6()1602 extend to the central office and terminate on contacts of a cut-off relay B through which they are normally connected to a line relay R and battery on one side and ground on the other. The arrangement shown is the so-called two wire multiple, with extensions 603 and 60410 the jack 600, with which coiiperates a plug 651 having its tip and sleeve conductors connected to the cord conductors 696 and 697, terminating-anthe condensers 652. Tip and sleeve relays R and R are provided as is usual with this type of cord and jack.

.The relay R controls .the circuit of the supervisory lamp 605 and the release cir- 65 cuits 606-607 for the automatic switches in Fig. 1, these circuits being connected to the trunk conductors 608609 extending to the first selector switch S, which has the usual vertical and rotary relays R and R, private magnet M test relay R release magnet M talking wipers w" w", test wiper 00, side switch arms 610, 611, 612, and 613, vertical magnet M and rotary magnet M The second selector switch S has relays, magnets, and contacts corresponding to those of the first selector with the exception that the vertical and rotary relays of the second selector when simultaneously energized close their own release circuit and also a branch through the test bank and test wiper of a first selector temporarily connected therewith, to the release relay of said first selector. The connector switch S has vertical and rotary magnets 35 and relays, and a test onprivate normal magnet, similar in other functions to those of the selectors. The vertical and rotary relays control their own release circuit and also the back release the same as in the second selector, but the functions of the magnet M include the test of the line wanted, and the release of the switch if that line is busy. The trunk wires 615-616 of the connector terminate at the condensers 619 and on the switch side of the condensers the conductors 617 and 618 are extended through contacts of the ringing relay R to the side switch arms 620 and 621, by which they are connected during conversation to the talking wipers c.o "'-w and thereby connected to the contacts of the wanted line. Further detailed description of the line and cord circuit in Fig. 1 and the general switch circuits in Fig. 1 will not be given, as none of the features so far mentioned form any part of the present invention, except in so far as they contribute to completeness. The circuits illustrated in Fig. 1 are those of the ordinary well known Strowger system, employing selector switches of the type shown in Letters Patent granted to Keith and Erickson March 13, 1906, Nos. 815,176 and 815,321. In order to enable the connector circuit of Fig. 1 to be employed with a two wiremultiple line circuit as shown in Fig. 1, the Strowger circuit is modified by the introduction of condensers 619, the tip and sleeve relays R" and R and the ringing relay R with its interrupter I and lockout relay B. These parts are substantially as shown and described in my prior application Serial No. 428,865, filed April 23, 1908, and also form no essential part of the present invention.

For the purposes of the present invention, and in order to enable each of the switches S, C and S to generate its own actuating impulses, I provide the vertical magnets M and M with interrupter contacts .2: controlled by the magnet armature, these contacts in each case being normally closed and included in the circuit of the vertical relay 'R or R. In the case of the connector, the vertical androtary magnets M and M are each provided with interrupter co'ntactsa', both pairs of which are,

normally closed and included in series in the circuit of .the vertical relay R The result of this arrangement is that without other change in any switch, when any one of the actuating magnets is. properly connected by means of the side switch, 1t will make and break the circuit of its associated controlling relay, which in turn will make 62S, 62!), 630 and 631, each of which is fitted with means for turning it through different determinate angles by hand. In the diagram the means indicated are arms wvith finger holds which serve also as point ers to sweep over numbered arcs. Connected to each diskis a ratchet or star wheel 632,

633, 634 or 635. These are controlled by anchor eseapements carried on the armature levers of electromagnets 636, 637, 638 and 39. Associated with the disks are relays 640, 641, 642 and 643, controlling the actuating magnets and responding to the line impulses in succession. Each disk has a. retractile spring, and each scape wheel has a. portion of its surface smooth, vto permit the spring to move the disk back some distance after the working impulses cease. During this extra movement of each disk it carries a tooth 644, 645, etc., past contacts erabl'e number of trunks 608 609.

Fig. 1.

ment with other contacts which shift the control circuit to the next disk. R is the starting relay, which connects the vertical androtary wires 648 and 649 to the trunk wires 608 and 609, in response to the actuation of the starting key 650. In addition to thecontacts of this relay I have shown a key 651 individual to each trunk, so that the sender 627 may be used with a consid- This mode of connection however is intended merely for descriptive purposes and not as trunk wires 608609 and the line wires 601 602 may bereplaced-by any desired primary selecting means, such as'shown in any of the applications herein named; or

the line may be connected direct to the trunk conductors, with condensers 652 interposed if desired. The sender 100 may also be located at asubscribers station as well as at Ea central oflice, the necessary changes to cited this or other modifications referred to being well within'the scope of any telephone engineer or circuit man.

In Fig. 1 the sender 627 of Fig. 1 is substituted by a setof key strips K K, K and K -similar to those shown by my application herein referred to. Associated with each strip of keys is a step by step switch, 414, 415, etc., operated over the same circuits as the disks 628, 629, etc., of The called subscribers number is set up on the key strips in the usual manner and the connective operation of the switches started by the closure of the starting key SK, in the actuation of the starting relay R. Magnets M, M, etc., are the stepping magnets for the switches 414, 415, etc., respectively, and magnets M, M, etc., are the corresponding release magnets. Relays R R, etc., are the repeating relays which are actuated in synchronism with the repeating relays of the several switches and correspond to relays 640, 641, etc., of Fig. 1. Relays R R etc., and R, It, etc., are circuit shifting relays which subserve similar functions to those of the springs 662, 663, 664, etc., of Fig. 1.

Fig. 1 is a diagram of a SIll)SCl'll)0l"S terminal apparatus and operatofis listening equipment, similar to that shown in Fig. 1. and to be usedin conjunction with Fig. 1.

The operation of the apparatus and circuits in Figs. 1 and 1 is as follows: The subscriber 653 calls by closing his line circuit, relay R lights its lamp, plug 654 is inserted in jack 600, relays R R 9 areenergized in series, relay R is energized, and the operator ascertains the number wanted in the usual or any desired way. If key 651 is employed, it is actuated to cut off the trunk from the cord, and connect conductors 608-609 to the contacts of the starting relay R". The number Wanted is then set up by turning the disks 628, 629, 630 and 631 until their respective arms or pointers rest over numerals corresponding to the several digits of the number. The turning of these disks completes the circuits of their respective relays 640, 641, etc., and turns the ratchets 632, 633, etc., through angular distances corresponding to the several digits. The starting key 650 being de ressed, circuit of relay R is closed as fol ows: B, 655, 656, 650, 657, R", ground, B. The energization of relay R connects 649 to 658 and 648 to 659, and the relay locks itself on wire 660. Circuit is then completed-from the battery to the switch S in Fig. 1 as follows: E, 655, 640, 661, 662, 663, (628 being off normal) 649, 658, 608, (into Fig. 1) 611, contact ac of relay M", It, ground, B. Magnet R is energized, closing circuit of M, which is energized and breaks the contacts m apart at the end of its stroke, but steps the switch spindle and wipers up one step before breaking. The separation of contacts :0 opens the circuit of. relay 1%, which becomes de'e'nergized and in turn opens the circuit of magnet M, which becomes deenergized and closes contacts 00 thereby closing the former circuit of relay R, which again becomes energized, again energizes magnet M and so on, the stepping up of the switch S and the making and breaking of the circuit at a: being repeated so long as the springs 662-663 in Fig. 1 remain closed. These springs are opened when the arm of disk 628 has been returned to zero, which requires as many current impulses as the forward steps through which it was moved in setting. As each current impulse is produced in the actuation of the switch S one step, it is obvious that the switch has been set forward .or upward a number of steps corresponding to the digit previously determined.

The disk 632 has ratchet or star teeth only part way around its circumference, there being ten teeth on each side and smooth spaces intervening. This is for the purpose of permitting lost motion after the number has been received, so that the spring sets 664665 and 662-663-666 may be operated in succession. The closure of the first named set produces a rotary impulse for the switch S" through the following path: B, 655, 672, 664, 665, 648, 659, 609, 612, R, ground, B. B becomes energized and closes the circuit of M, which becomes energized Mill and steps the side switch arms all around one step, shifting the trunk wire 608 onto a dead contact and closing circuit of rotary magnet M whichrotates the spindle and wipers to find an, idle trunk to a second selector, in the ordinary manner. In the meantime the disk 628 being forced past spring 664 by. its retractile spring, shifts wire 649 from relay 640 to the path 667, and thereby connects relay 641 to the trunk 608. When an idle trunk has been found, the side switch of selector S takes its last step, as

Well understood without explanation, and

the trunk wire 608 is at once connected to 693, whence a circuit is established from 629 to S as follows B, 655, 641, 685, 675, 669, 667, 666, 663, 649, 658, 608, 693, m, R ground to B. The operation of selector S then ensues in precisely the same manner as that of selector S and when the disk 629 reaches zero position a rotary impulse is sent over the path: B, 655, 690, 673, 674, 670, 648, 659, 609, 694, R ground, B. Selector S then finds an idle trunk to a connector S wire 693 in the meantime remaining open at the side switch, and at the end being connected to 615. A path for the third set of impulses is then closed as follows: B, 655, 642, 686, 679, 677, 671, 668, 669, 667, 666, 663, 649, 658, 608, 693, 615, contacts M and M in series, R ground to B. R actuates the magnet M to step the switch up to the desired row, when the disk 630 operates as the preceding disk mechanisms, did, to cut off relay 642, send a rotary impulse and shift the circuit 671 to the next path, 687, leading to the relay 643. In the'connector the side switch has shifted in response to the rotary impulse at ar, so that M is cut out and M is cut on to be controlled by R Further impulses from follow this path: B, 655, 643, 687, 684, 695, 678, 677, 671, 668, 669, 667, 666, 663, 649, 658, 608, 693, 615, to relay B through rr.'1:. Magnet M then steps the switch around to the wanted linc terminals and the next rotary impulse causes the line to be tested, and if clear the side switch takes its last step, 620. and 621 connecting the trunk wires 617 and 618 to the line through wipers M -u Relay R connects the ringing relay to battery, the inter rupter I causes its intermittent energization, the wanted subscriber is rung. and when he answers the relay R causes the energization of the lockout relay R and conversation proceeds. In the meantime. the final step of disks 635 and 631 after sending the rotary impulse over wire 670 opens 687 at 684647, and also opens. the locking circuit 689-660 of relay R", 'whereby the sender 627 is entirely cut oti'from the trunk wires 658659, 608-6()9. The operator may then throw up the key 651. or if this key is replaced by an automatic secondary selector of the type set forth in my prior applications referred she will not have to perform any act, but merely wait to receive other calls.

The operation of the switch control as embodied in Figs. 1 and 1 is as follows: The operator upon perceiving the call signal plugs in on the calling line, operates the key 651 (Fig. 1 and after ascertaining the number of the wanted subscriber, all in a manner as previously described, sets up the number on the key strips K, K, etc., and depresses the starting key SK. Assuming that the number wanted is 2463, the operator closes the second key 10 in the strip K is in K, It in K, and 7: in K, and upon closure of the starting key SK, the starting relay R is energized and locks itself to ground through armature r looking wire 418, and armature 1. The attraction of armature r connects the relay R in series with the tip impulse wire 658 so that itwill be actuated in synchronism with the tip relay and associated stepping magnet of the first selector (Fig. 1) in the same manneras above described. The circuit of relay R may be traced as follows: battery, R 419, 1 420, 1 tip impulse conductor 658, contacts of operators key 651 (Fig. 1") and over tip conductor 608 to the circuits in Fig. 1 as above traced in the previous description of operation. Each actuation of relay R completes the energizing circuit of stepping magnet M which actuates to step around the spindle of switch 414, and with it the wiper 421 engaging the contacts successively, one at each actuation of the magnet M The switch 414 thus steps in synchronism with the controlled selector switch and upon engagement of the wiper 421 with the second contact in its bank, the circuit of relay R is completed over the following path: battery, R 422, key k of strip K, 423, second contact of switch 414, wiper 421 to ground. Relay R upon energization, attracts its armatures looking itself to ground through armature T 424 and contacts of ofi normal switch 425. The attraction of armature r completes the circuit of release magnet M, from battery through 425, 426, 427, M to-ground, and the attraction of armature r completes the circuit 'of relay R, from battery through'r locking wire 418, R 428, r to ground. magnet M releases the switch 414 and remains energized until said switch assumes its normal or zero position and opens the contacts of off normal switch 425, whereupon relay R" is denergized, and in turn decnergizes said release magnet. Relay R upon actuation locks its circuit to ground at r and shifts the impulse conductor 420 out of connection with R and into series connection with relay R, which connection to battery lead.

The actuation of the release tor 420, r t 429, W, 430, R 431, 1' The actuation of relays R and R occurs immediately after the second step of the first selector switch, and before the interrupter contacts w have closed, and simultaneously with the completion of the circuit of release magnet M" a battery shifting impulse is sent over the sleeve conductor to actuate the private relay of the first selector, in a manner well known. The circuit of this shifting impulse may be traced as follows: battery, r-, 425, 427, 7- 659 through operators key 651 (Fig. 1 and over sleeve conductor 609 to the circuits of the first selector (Fig.

7 1), This impulse endures during the res- .toration of the switch 414 and upon its cessation the private magnet is de'energized,

and the first selector switch started to test for an idle second selector. During testing the tip and sleeve circuits are opened at the side switch contacts, so that no current can flow through the impulse conductor 420 until after connection is made with a second selector trunk, whereupon the tip circuit is completed through to the circuits of said second selector, and the relays R (Fig. 1) and B (Fig. 1) are intermittently energized, in series, in the same manner as that previously described for relays R and R. The circuit of relays R and R may be traced as follows: battery, (Fig. 1), 1' 431, R 430, 1' 429, w, 4.20, a 658, through Fig. 1 as previously traced, into Fig. 1, tip conductor 608, side switch 611, 10 693 and thence through interrupter contacts a: and relay R to ground.

Switch 415 is stepped around in the same manner as was the switch 414 until its wiper 432 engages the fourth contact of its associated bank, whereupon the relay R is energized, its circuit being from ground through wiper 432, wire 433, key of the strip K, 434, B through battery lead to battery and back to ground. The energization of R releases the switch in a manner as before described and completes the circuit of relay R" through the armature r and relay R in turn opens the circuit of R at T and connects the wire 429 to the wire 435, so that the relay R which controls the third set of number impulses is connected in series with the tip impulse conductor 420 through armature 1' 429, 1 435, 1' 436, R, 427, 7' to battery, which circuit is finally completed upon the de'c nergization of R and after the second selector has completed its testing and be comes connected with an idle connector, the

test impulse having been sent over the sleeve circuit upon the attraction of armature 1' The switch 416 now steps around in synchronism with the primary stepping motion of the connector until the wiper 438 engages the sixth contact of its associated associated bank, key is of the strip 1 conductor 439, R to the battery lead The relay R becoming energized, sends the shifting impulse over conductors 426 and 427' through armature 1- and energizes B through r and R in turn shifts the tip circuit from the relay R to relay R by the attraction of its armature r After the private normal magnet of the connector switch has operated and the side switches stepped to their second position in the usual manner, the relay R is energized in series with the rotary relay of the connector switch in a manner similar to that described for the other control relays, the connection ofR in series with the tip circuit being from battery lead, through r wire 440, R 441, 442, T 435, and so on as before described. The switch 417 new steps around in synchronism with the secondary or connective movement of the connector switch, and so continues until the wiper 445 engages the third contact when circuit of relay R is completed from ground through the wiper 445, the third contact of its associated bank, 446, R and through battery lead to battery B. Relay R upon energization locks itself through the off normal switch of 417, and connects battery to the impulse wire 426 sending the final test impulse over the sleeve circuit in a manner as before described. The relay R also connects battery to the locking wire 418 through armature 1' and energizes relay B through armature 1, R locking itself to battery, through armature 1' of the start ing relay R, the latter being held energized .on the common locking circuit 418. The attraction of armature 1' opens the circuit of R which brings the wipers of the connector switch to rest on the third contacts of the sixth row which lead to the wanted substation. As the release magnet M is maintained energized by current over the impulse wire 426, the switch 417 is permitted tomove back to its normal or zero position whereupon the off normal contacts of said switch are opened and the relay R is deenergized. -The retraction of armature 1' removes battery from the impulse wire 426 which deenergizes the release magnet M andpermitsthe side switch of the connector to move intothe third or final connective position and the attraction of armatures r and r removes battery from the common lockin wire 418, and opens the energizing circuit of B respectively. Upon the removal of battery potential. from the common locking circuit 418, relays R R, R and R are deenergized, and upon the retraction of armature 1 of R the look ing circuit of R is opened, which then be comes deenergized whereupon all the apparatus and circuit of the impulse controlling device are brought to normal condition and the operator is ready for another call.

Referring to Fig. 2, each line circuit 1-2 is provided with a line relay R and a cutoff relay R which when energized disconnects the line relay R and connects the tip and sleeve sides of the line to its multiple bank contacts in the primary and connector switches of its group. The attraction of the armature r of the relay R connects ground to the individual test contacts of the primary switches S The attraction of armature r locks the relay R on short circuit to ground through armature r of relay R which prevents interference by the subscriber in case he should move his receiver hook. The line relays R are divided into groups of ten and the windings of each group are connected in.

multiple to the winding of a relay common to the group, which when energized connects ground to the row contact -of the primary switch through the armature 1, thus designating the group of lines calling, while the relay R designates the particular line in the group. Each group of one hundred lines is assumed to have access for calling purposes to ten primary selector trunks, such as shown in Fig. 3, and to be accessible for calling through ten connector switches such as shown in Fig. 4. Thus, each line has twenty sets of multiple contacts, ten in primary selector banks, and ten in the connector banks. The primary distributing switch S determines which trunk in the group of ten being idle, shall respond to any particular call in its group of lines; and one of these primary distributing switches is therefore required for each group of one hundred lines, with its ten trunks. Associated with each primary distributing switch S there is a secondary distributing switch S and a kick-off switch S. The function of the secondary distributing switch is to pick out an idle opera'tofis circuit and start the same to testing for the group of primary trunks over which the call originates. This can be done because there being only one switch S for each group of one hundred lines, that is to say for each group of ten trunks such as shown in Fig. 3, and since it is convenient to arrange the con tacts of each group of ten trunks in one and the same row in the secondary selector switches S (Fig. 5), each secondary distributing switch can therefore be directly identified with its own associated row of primary trunk contacts in each of the secondary switch S its second contact 8 Wired to number one row contact of the second secondary switch S and so on. Number two switch S belonging to another group has its first contact 8 wired to number two row contactof the first secondary switch S its second contact s 'wired to number two row contact of the second secondary switch S and so on. In an exchange of one thousand lines the contacts 8 of the tenth switch S are wired to number tei'i row contacts of the secondary switches S The relay R has one terminal of its winding connected to the wiper arm we of the switch S. When the arm we in rotating finds an idle primary switch S the relay R is energized in series with the relay R (Fig. 3) and opens the circuit of stepping magnet M, thus bringing the switch S to rest.v The energizing circuit of relays R and R may be traced from battery B (Fig; 3) 34 35 36 .151 R13 (38 Fig. 2), s, we, 39, R240, 1', to ground. The energizing of the relay R causes the switch S to immediately start to pick out an idle. secondary switch S". The switch S can be testing for the calling line while the switch S is testing for the trunk 'shown in Fig. 3. The relay R acts somewhat as the line relay R, connecting battery to its individual test contacts in the switches S Referring to Fig. 3, the relay R is the row test relay, and is energized when the wiper 10 finds an active .contact, disconnects rotary relay R and in its place connects vertical relay R The relay R is used in testing for the individual contact as well as a battery supply relay for the calling subscriber. When energized this relay disconnects the row relay R The deenergizing of relay R disconnects the relay R from the test wiper w? and connects it to the sleeve wiper w in series with the cut-off relay R Relay R is-the tip battery supply relay and controls the release magnets M and M after the first selector switch S has .moved off-normal. The relay R is used for opening the talking circuit while I the impulses are being sent to operate the outgoing switches. This relay also with R jointly controls the relay R Relay R is the test relay having its locking contact 7 connected to the test wiper w Its circuit is initially. closed through the contacts of relay R and foot springs 144 and 145 After the switch S makes its first vertical step the circuit of this relay is maintained through contacts of relay R and test wiper 20 so long as this wiper encounters busy contacts, which are grounded through other switches.

Referring to Fig. 4, relays R and R are impulse relays reciprocally controlling and controlled by magnets M and M. Relay R provides the first set of impulses betact of relay R Relay R also closes circuit of relay R This latter remains energized until the called party answers or until the calling party hangs up his receiver. In case the called-for line is busy, relay R will be denergized by action of test relay R Relays R, R and R all have their circuits completed to ground side of battery through test wire 200,- contacts 0", w, r to ground. When the calling party hangs up his receiver after failing to get his party, switches S and S are restored and ground removed from test wire, causing deenergization of any of the relays R or R which happen to be locked. The switch S is restored to normal after the called subscriber hangs up his receiver or when the relays R R and R are deenergized; and just before it reaches its normal position the wiper arm ws passes over a contact and closes the circuit of. the release magnet M restoring the connector switch S to normal position. Thus the connector switch S has a quick release if the called-for line is busy, and after the called party answers a slow release by switch S Referring to Fig. 5 relay R is the row test relay and R the individual test relay. Relay R is the control relay and corresponds to relay R (Fig. 3). Relay R is the signal relay and pulls up in series with relay R (Fig. 3) after the primary trunk has found the line and the secondary switch S has found the trunk. The operation of this relay closes the circuits of the signal lamp L (Fig. 6), the guard lamp L and the night alarm bell. Relay R is the listening relay actuated by listening key LK. Operation of this relay deenergizes relays R and R and closes circuit of listening lamp L. Relay R is the starting relay and is energized in series with R by the pleting the circuit of release magnet M restoring switch S to its normal position. Relay R is the trunk start relay and is also used for release in case the calling subscriber has hung up his receiver or if theoperator fails to get a response after pressing the listening key. This relay R is energized by key RK, which also actuates relay B. These two relays being energized at the same time remove battery connection from the first two contacts over Which arm ws sweeps. The first selector switch S upon receiving the first rotary impulse through one of the buttons of the strip K closes the foot springs 175 and 176. The closure of these springs while relay R is deenergized completes the circuit of release magnets M and, M causing the release of switches S and S Referring to Fig. 6, number one key of each'strip is connected to the first contact on the impulse receiver S which takes one step at each impulse sent back from the switches; number two key to the second contact, and so on to number ten key which is connected tothe tenth contact. Each strip of keys has a common wire connected to one contact of each key in the strip and leading to its proper contact on one or the other of the controlling relays associated with switch S The order in which these are arranged to transmit impulses in proper sequence is as follows: At the first rotation of the impulse receiver the first strip of keys (hundreds) is connected to the tip side of the trunk; second rotation, ten test impulses to impulse receiver over sleeve side of trunk, third rotation, selective ringing strip K" connected to tip side of trunk; fourth rotation, keys K (tens) connected to sleeve side; fifth rotation, keys K (units) connected to tip side of trunk; during the fifth rotation and just after the units impulses have been sent, a single test impulse is sent to sleeve side of trunk; sixth rotation, arm ws" engages contacts connected to battery energizing rer lay R This relay unlocks R restores switches S and S thus disconnecting secondary switch S from the primary trunk in Fig. 3.

The operation of the circuits shown in Figs. 2, 3, 1, 5 and 6 is as follows: The subscriber at station A desiring a connection lifts receiver R from hook H-which bridges his telephone across line wires l2, energizing relays It and R by way of B, 19, 20, It, 21, R 22, R I, station A, 2, r, 23, ground to battery. Relay R locks to ground through 1, 21, and r, and connects ground to individual test contact 1: through 25 and 1' while B connects ground to row test contact 0 through 26 and r and completes circuit of group lam L and relay R the former from B, 19, 2 L, 28, 7' 2, ground to battery, the latter from B, 19, 29, R, 30, 7'

and completes circuit of R over path B to ground. Lamp L lights, and relay R completes circuit of stepping magnet M to interrupter I for intermittent energization over the path B, 19, M, 31, r, 32, r, 33, I to ground. Magnet M moves switch S step by step until wiper 10s engages a contact s connected to relay B (Fig. 3) of an idle primary selector trunk, whereupon relays R and R (Figs. 2 and 3), are energized by current through B (Fig. 3), 31, 35, 36, r 37, R 38, (38 Fig. 2), s, ws, 39, It, 10, r, to ground. Relay R opens circuit of magnet M at '1', looks itself to ground through r 7 19, 11, R 12, R and ground. Relay R locks itself to battery through 1*, 13, W, 11, and 31 to B; connects battery to one terminal of relay R through 31, 35, r 15,-

16, 1' 17, and 18; and also completes circuit of rotary relay B through r and inter-- rupter I, so that this relay is energized intermittently its circuit being; B, 31, 35, 1 15, 16, 7 17, 19, 50, R 51, 97 52, r I to ground. At each actuation of relay R magnet M is energized by current from B, 31, 57, contacts 58 of foot step switch F 59, M, 53, 1, ground, stepping primary selector switch S around until wiper w engages row test contact 0 whereupon relay R is energized over circuit B (Fig. 3), 31., 35,7" 15, 16, 7- 17, 18, R 19, 20 0 (Fig. 2), 26, 7*,ground to battery. Relay R locks itself to ground through r connects test wiper L0 to sleeve relay R through 51, 7' and 55, and shifts interrupter I from rotary relay R to vertical relay R at 1' so that R is intermittently energized over the circuit; B, 31, 35, T 15, 40, 7- 17, 49, R 56, 1' 52,1 I ground to battery: At each actuation of relay R vertical magnet M is energized over the path B, 31, 60, M, 61, r to ground, stepping switch S" up until wiper nf-' engages individual test contact 0 (Fig. 2) whereupon sleeve relay R is energized over the circuit; B (Fig. 3), 31, 35, R 55, r 51, w, 0 (Fig. 2), 2'), r (of relay R), ground to battery. Relay R connects battery to trunk conductor 7, by way of r 63, 61, 7' 65, and resistance r, and at the same time opens the circuit of relay It at 1- Relay R opens circuit of vertical relay R and magnet M is dee'nergized,which permits wiper m to stop on contact 0 wipers w and w engaging contacts 0'' and respectively. Tip relay R is now energized through subscribers telephone in series with R Simultaneously with the selection of the calling line as described, distributing switch S (Fig. 2), is stepped around in Search of an idle secondary selector, by ma gnet M in circuit: B, 19, 11, 66, 67, 68, r", 61, M 70, 7", 71, I to ground. Switch S coii tinues to step around until wiper arm nusengages a contact 8 connected to an idle til wiper 10 engages contact 3 secondary selector, whereupon relays R and R (Figs- 2 and 5) are energized in series, the circuit being: B (Fig. 5), 86, springs 7374 of operators jack J, 75, springs 76-77 of foot step switch F 78, It, 79, through Fig. 3 into Figs. 2, 3 10 80, 81 R 82, z' 'to ground. The actuation of relay R causes the energization of relay R, the circuit being: B, 19, 41, 66, 67, W 83, 84, R, 85, r to ground. Relay R locks itself to battery through 7", and opens circuit of magnet M at r, whereupon switch S comes torest with wiper arms 108 we and 703 resting on contacts 8 3 and 3 respectively. i

The attraction of armature r of relay R connects battery to wire 99, which completes part of the row test circuit, and the attraction of arm.'ature r completes the circuit of relay R as follows: B to R 223, r to ground. Relay R grounds wire 80, shunting relay R out of series with relay R (Fig. 5), the circuit of the latter relay now going direct to ground by way of wire 80 and armature 1%". Relay R (Fig. 5) completes the circuit of rotary relay R through interrupter I, so that said relay is intermittently energized by current over B, 36, 37, 1 33, T 39, R 90, 5 I to ground. Relay R also connects one terminal of relay R to ground through 91 and T and locks itself to battery through 92, 1' 3, 93, 2 87, 86, B. Each actuation of relay R energizes rotary magnet M through B, 86, 94, M 95, r to ground. Magnet 1V1 steps switch S around imhe first rotary step of the switch S disconnects contacts 76 and 77 of switch F" and connects contacts 76 and 290, which opens the initial energizing circuit of relay R, (that relay, however, remainin energized through its locking circuit and closes the circuit 'of off-normal lamp L as follows: B, 86, 73, 74, 75, 76, 290, L to ground. When wiper 70 engages contact 3 the relay R is energized over the path: B, ground to T (of relay R 91, 96, R, 97,110, 3 98, through Fig. 3'into Fig. 2, 3 (in switch S 1082, 99, 1' 68, 67, 66, 41, 19, battery. Relay'R locks itself to battery through: 100, 1 101, 33, 2 37 and 86,

opens circuit of relay R and closes circuit of relay 1 at 1. Relay R opens circuit of magnet l) 13 at 7 which stops switch S with wiper w. engaging contact 8 As circuit of relay R is completed at T said relay is intermittently energized through: B. 33, 37, r 33, 7 102, R5", 103, 90, T I, ground. Each actuation of relay R energizes vertical magnet M through! B, 86, M, 104, 7', ground. Magnet M steps switch S up until wiper w engages contact 3 whereupon relay R is energized through: B, ground to r (relay R 91,

R 105, w, 8 4.5 (4.5, Fig. 3),1- 35, 345 battery. Relay R opens locking circuit of relay R atv alsoopens circuit of relay R at 1' 7" of relay R opens circuit of verticalmagnet M, which stops switch S with Wipers w, w and 'w on contacts 8 s, s and 8 (Wiper w is raised off row contacts by first step). Wiper w engaging contact 3 (Fig. 5) 'relays R and R, (Figs. 5 and 3) are energized through: B, (Fig. 3), 34, 35, 36, 1' 63, 106211, 107, (107 Fi 5), s, w 108, 5 100, T 111, 112, R, 113 1 114, W, 115, W, 116, r ground. iRelay B, when actuated, opens series circuit of relays R and R (Figs. 2 and 3) at 1 Relay R disconnects interrupter I at r and relay R (Fig. 2) opens circuit of relay R at 1". Relay R denergizing opens circuits of magnet M relay R and relay R while relay R its circuit opened It/ opens circuit of stepping magnet M at'r. This prepares distributing switches, S and S with their relays, for another call. Be-

lay R becoming energized closes circuit of.

nightalarm through: B, 86, 110, 117, 118, 7' 119, W, to ground; closes circuit of guard lamp L (Fig. 6) through B (Fig. 5), so, 110, 117, 118, T8, 120, 121 (121 Fig. 5), L to ground; closes circuits of service meter E (Fig. 5) through B, armature 1 122, 242, and magnet of'service meter E to ground; and line lamp L (Fig. 6) throu h (Fig. 5) i 122, 123 (123 Fi 6), a to ground. The operator, perceiving the signal, depresses listening key LK (Fig. 6) energizing listening relay B (Fig. 5) through: B (Fig. 5), 86, 87, T 88, 101, 1' 124, R 125 (125 Fig. 6), contacts of key LK, to. ground. Relay R energizing, opens series circuit of relays R and R at 1' and locks itself to ground through w and 114, as previously traced. Relay R deenergizing, opens circuit of relay R at 1' Relay R completes the operators listening circuit as follows: receiver OR, 127, plug P, tip P, spring j,: 128, T 129, 131, 10 3 130 (130 Fi 3),1" 133,9, 4.22, 7, condenser C 5, w, c (Fig. 2), 3, 1', line wire 1, subscribers telephone, line wire 2, 1", 4, c", to, (Fig. 3), 6, condenser C 8, 10, 134, a 135 (135 Fi 5), 831, 711 3132, 136, 1' 137, coil 10, 138, jack spring 7', plug sleeve 11, 139, receiver OR.

The operator, on ascertaining the number wanted sets up the same on her ke set, (Fig. 6), by depressing the key in strip K corresponding to the first digit, that in the strip K corresponding to the second digit, that in the third strip K corresponding to the third digit, and that in the strip K corresponding to the particular ringing genera-tor to be selected, and then actuates starting key, SK, whereupon starting relay R (Fig. 5) is energized in series with trunk cut-of]? relay R (Fig. 3) through: ground, 126, (Fig. 6) key SK, 140, (-140 Fig. 5) R 141, 111, 1' 109, 1 108, w, 8 107, (107 Fig. 3), R 106, 63, 1 35, 34, battery to ground. Relay R opens trunk conductors 97 and 108 at r and 1' and energizes relay R through: B, 34, 44, T 142, R 143, contacts 144 and 145 of switch F to ground. Arinatures r and r connect the impulse wires 130 and 135 to rotary and vertical relays R and R respectively, while armature r connects conductor 147 to one terminal of relay B through contact 146. Starting relay B (Fig. 5) takes ground ofl' relay B through 114, at 1' and locks itself through 148, 361 and 115 to ground as previously traced. Armature r connects starting wire 151 to stepping magnet M through: E, (Fig. 5) 86, 110, 117, M 153, T 152, T starting wire 151, (151 Fig. 6) contact d to ground; so that said magnet is momentarily energized, stepping switch S forward one step. This first step of the switch S brings the wipers 101 108 and 108 into engagement with the first contact 18 etc., of theirrespective banks. The wiper arm we connects ground to the common wire 405 of key strip K (Fig. 6), and relay B (Fig. 5) is energized by current from B, 86, 108 18 401, 402, R to ground. The actuation of R connects the tip conductor 131, to the common impulse conductor 403 at T which completes the circuit of relay B (Fig. 3) over the following pathzB (Fig. 3), 34, 60, 194, R m 174, W 130, 130 (Fig. 5), 8 131, 1 103, 403 (Fig. 6), R 404, 1 to ground. Helay R upon actuation completes the circuit of rotary magnet M which upon actuation steps the switch spindle and wipers around one step and at the end of its stroke opens the circuit of relay R at m. R becoming deenergized opens the circuit of M which upon deenergization .closes the former circuit of R which again becomes energized and again closes circuit of M and so on, the stepping of the switch spindle and the breaking and making of the circuit of R continuing as long as the wire 404 (Fig. 6) remains grounded'through armature a As. the relays R (Fig. 3) and R (Fig. 6) are in series, each time'the relay R is energized the relay R isenergized and completes the energizing circuit of stepping magnet M of switch S at armature contact 1, stepping the switch arms s s and 8 around one step at each step of the selector switch S Assunr ing that the digits set up on the key strips K K K and K are 2, 4, 6 and 3 respectively, the switches S and S will continue to step around in synchronism until the wiper 8 of switch S5 engages contact 07 whereupon relay R is energized by current over the following path: B, R, 406, 8 (P, 107, 408, 71 105, 105 (Fig. 5) switch arm Q0830 to ground. The relay R upon energization attracts its armatures 7 W and r locking its circuit through 409, W, 410 to ground through restoring contacts 03* and arm .9 The attraction of armature r opens the series circuit of relays B (Fig. 3) and R (Fig. 6) which brings the switch S to rest with its wipers beneath the secondrow of contacts and opens the energizing circuit of M (Fig. 6) at 1. The attraction of armature r completes the circuit of M through interrupter I so that the switch S continues to step around until the wiper arms 8 8 etc., assume the normal or zero position as shown when the locking circuit of relay R is interrupted between contacts d* and arm 8 and relay R releasing its armatures again opens the intermittent circuit of M at 1. At the first rotary step of switch S contact springs 175-176 are closed, partially closing the release circuit through magnets M and M When the switch S assumes the position shown, the arm .9 again engages contact (Z again energizingmagnet M (Fig. 5) which steps the wiper arms 108 708 etc., around into engagement with the second contact of their respective banks. The wire 411 is con nected to ground through wiper arm 108 which energizes relay B (Fig. 6). The actuation of R connects conductor 412 to ground through 1' and connects conductor 406 to ground at r which energizes relay R The relay R upon actuation locks itself .and maintains the continued operation of 'the switch S around to normal position in a manner as before described.

Simultaneously with the energization of relay R the relay R is energized by current from B, 86, we, 28 412, R to ground. The actuation of relay R connects the conductor 132 to conductor 403, and the energizing circuit of relay R (Fig. 3) is completed as follows: B, R, 199, 1 2135, 135 (Fig. 5) 8 w, 132, contact of R 403, 403 (Fig. 6) to ground through 7' Relay R and vertical magnet M are now inte-rmib tently actuated to step up the spindle of switch S in the same manner as R and M operated to step it around, the stepping up continuing so long as the relay R remains energized. At the first vertical movement of the spindle of switch S the circuit of relay R is opened at contact springs 144 and 145 of switch F and should the connector trunk (Fig. 4) be busy because of the wipers of another first selector switch resting on the multiples of contacts 0 9", relay R would remain energized through: B (Fig. 3), 31, 11, 1' 112, R 146, 1*", 117, 10 0 (Fig. 4) to the multiples of 0 and thence through the circuit of the other first selector by way of its wiper 'w (as in Fig. 3), 147, r ground, to battery. The armature r of relay R, remaining attracted permits the vertical relay R and magnet M to step the wipers up to the next set of contacts, and so on until an idle connector is reached, when, relay B being deprived of ground, releases its armatures. The armature r disconnects Wire 1335 from the relay R stopping switch S with its wipers w", 10 and 10 on contacts 0 0 and 0 respectively, of the connector trunk (Fig. 4). The wires 130 and 135 are now connected to the tip and sleeve conductors 9 and 10 through armatures r and T respectively, and contact 0 (Fig. 4) and its multiples are connected to ground through @0 (Fig. 3), 147 and r The switch S upon assuming its normal position again completes the circuit of magnet M through contact d and wiper arm 8 and steps switch S around to bring its wipers into engagement with the third set of contacts. Ground is now connected through wiper 'ws to wire 430 common to the keys of strip K and the circuit of relay R is closed through wiper we and wires 401402. The actuation of R completes the circuit of relay B (Fig. 4) and R (Fig. 6) in series over the following path: B (Fig. 4), 11 ,5444 m 443, m, 204, 1*, 16, 0 w (Fig. 3), 0, 133, 1' 130, 130 (Fig. 5), s* 20 131, a 403, 403 (Fig. 6) R 404, and to ground through 1. The attraction of armature r completes the circuit of stepping magnet M, which circuit may be traced from ground at armature T of R 215, 214, M 213, 212 and through oif normal. springs 211210 and battery lead to battery B. The magnet M upon actuation steps the generator selector switch around one step and at the completion of this operation opens the circuit ofrelay R at ma The relay R becoming deenergizedopens circuit of M which latter upon deenergization again closes circuit of R and this cycle of operations is continuously repeated, causing the switches S and S (Fig. 6) to step in synchronism, until the wiper 8 engages the third contact (1 which completes the circuit of 'relay R This circuit may be traced from battery B, through R, 406,

8 d 431, ,430, 430 (Fig. 5) to ground through wiper 87.0 Relay R is now energized and opens the series circuit of R and R which causes the switch S to come to rest with its wipers 8 ,8 and 8 in engagement with the third contact of their respective rows, while the relay R is held energized in a locking circuitthrough wiper of S and maintains the continuous movement of theswitch S until it reaches its normal or zero position, in the same .manner as before described, which results inthe deenergization of the relay R The first actuation of relay R energizes R and R the first through: B, 207, 1' 247, R 202, 200, 0 w (Fig.3) 117, r to ground, locking itself to battery through 249, T 250, T 207; the second relay through: armature T 230, R 235, T 236, 202, to ground, locking itself to battery through: 232, 1' 233, T 231.

The switch S upon assuming its zero position again energizes magnet M (Fig. 5) which steps the wiper arms of switch S around into engagement with the fourth contact, whereupon ground is connected through wiper 10s to wire 447, common to the keys of strip K and relay R is energized through wiper ws and. wire 412. R upon energization connects the relay B, (Fig. 6) and B (Fig. 4) in series. This circuit may be traced from battery B (Fig. 4), battery lead 231, armature 1' 233, r, 232, 230, R 448, m 228, w 15, 0, w (Fig. 3) 10, 1'34, 1' 135, and thence through the sleeve circuit of the operators control c1rcuit (Fig. 5) and through relay R (Fig. 6) as before described. The actuation of relay B (Fig. 4) energizes magnet M by completion of the following circuit: ground at armature, 1' 240, M, 239, off-normal conengages contact (0 which completes the circuit of relay B through key 76 of strip K and brings the wiper of the connector switch S to rest opposite the fourth row of contacts, while switch S continues to step to zero position; all in a manner as before described. The first actuation of B opens the locking circuit of B at 1' The first rotary step of switch S opens springs 210211 and closes 210246, which shifts battery lead209 from M to M lVhen the switch S again assumes its zero position the magnet M (Fig. 5) is again energized stepping the wipers of switch S around into engagement with their fifth contact, which connects ground to wire 449, common to the keys of strip K through wiper ws and energizes relay R through wiper was" and wire 450. The actuation of R connects the .sleeve conductor 132 to wire 451 leading to in which magnet M operated therewitlnthef circuit of magnet M being traced from: battery lead through ofi-normal contacts ground. -The relays R and magnet MW now operate to step the spindle of switch S vertically, the switch S (Fig. 6) stepping in synchronism therewith until the wiper s of S engages the sixth contact d? which completes the energizing circuit of relay R through contact 0Z contacts of key M of strip K and wiper 208 of S The actuation of R causes the connector switch S to come to rest with its wipers in engagement with the sixth set of contacts in the fourth row leading to the wanted substation, while S continues to step around to zero position, as before described. The first actuation of relay R again energizes R -through: r and R locks itself disconnectline multiples.

When the wiper s of S engages contact al a single test impulse is sent over the sleeve circuit from ground through wiper .9 contact (Z and over wire45l, 451 (Fig. 5), sleeve conductor 132 and so on to relay R (Fig. 4) as previously traced, whereupon if the wanted line is busy, with wipers w", w, of another connector switch, or 10 w of a primary selector switch, resting on multiples of contacts 0 0 the test relay B (Fig. 4) is energized, in the first case through: ground, 7- (F ig. 3), 147, @0 0 (Fig. 4), 200, 201, R, 251,), 252, 1 253, 18, w, 0 (see Fig. 2, the circuits of the called line being the same), to the multiple of 0 on which the other connector switch wipers are resting, thence through that connector (see again Fig. 6, this connector link being the same) by way of 18, 253, 1 252, a 259, R 260, 261, T 250, a 207, B, to ground; in the second case through: ground, R 0, thence through the multiple of c on which wiper w, of a primary selector is resting, 294, 7- 55, R 35, 34, B to ground. Belay B when energized locks itself to battery through: 262, 7 connects the busy back B2 to trunk conductor 16,

through 7 and 263, and closes the release circuit of S through: B, 206, 208, 209, 210, 246, 245, 264, 265, W, 267, 269, M to ground. M then releases the connector switch S. After this impulse relay R is denergized, and completes the restoring circuit of switch S through: B, 7 250, 1' 261, 270, T 271, W, 272,213, M ,214,1 273, we, 5 274, I to ground. Magnet M is intermittently energized until switch S reaches normal position when its circuit is opened between 608 and 5 The test relay R remains locked, holding busy-back B2 on trunk conductor 16, to signal the calling subscriber (Fig. 2), who then hangs up his receiver, opening circuit of B (Fig. 3) which deenergizes and energizes magnets M and M of switches S and S through ground, 175, 176, 166, 177, T142, 178, 179, M and M (in multiple), B, to ground. The switch S in restoring opens the circuit of B (Fig. 4) at 0 and w (Fig. 3) and the busy-back is disconnected.

If the wanted subscriber is not busy, R remains locked, and after the test impulse R de'e'nergizes, which energizes B (Fig. 4) and B (Fig. 7) in series, through: B (Fig. 4), 2 250, 7 261, 260, R 259, 7' 252, 7 253, 18, 10 0 (Fig. 2), 4, cut-ofi' relay R to ground. Relay R closes contacts r and mate, and 7- and mate,so as to connect the trunk conductors 15 and 16 to their extensions, 17 and 18, respectively. Simultaneously with the energization of R and R, ringing relay R is connected "through: B, W, 250, 1' 261, 270, 1' 277,

7 278, R interrupter I to ground. Immediately after the test impulse, the switch S arrives at its normal or zero position, and wiper s engaging contact (Z sends an impulse over wire 151, stepping switch S (Fig. forward one step bringing its wipers onto the sixth contact set. When 111.9 engages contact 68 the restoring relay R is energized through: B, 86, 110, 166, 6.6 to 98 ws 164, R to ground. Belay R opens circuit of R and R (Figs. 5 and 3 respectively), at r and r while r connects magnet M for intermittent energizatiOn through: B, 86, 110, 117, M 153, 165, I to ground. Magnet M steps switch S forward, holding R energized through 108 and contacts 68 to 98 until the wipers have reached normal position, as shown. The secondary selector switch S is restored by the cam on the switch S, in

bodiment of my invention now known to me but it is obvious that my invention may be variously embodied by those skilled in the art without in any wise departingfrom its generic spirit, and I therefore wish to cover by the annexed claims all such modifications to which by my invention I am legally entitled to! cover.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a telephone exchange system, a plurality of links containing automatic switches and adapted to be connected in series to join a pair of lines for conversation, a motor without the links and means to connect the motor with one of the links for operation in synchronism with a connected automatic switch, means determining the extent of operation of the automatic switch of a connected link in synchronism with the said motor, eans thereupon becoming active to return the motor to normal by continued 

